본 연구는 경남지역 야계사방사업지의 적지적소를 판정하기 위해 사방댐 총 526개소와 계류보전시설 총 230개소의 기시공지 및 시공예정지를 대상으로 입지 및 임상, 수문조건을 분석하였다. 사방댐 시공 지과 계류보전시설은 입지환경인자 중 퇴적암, 표고 201∼400m, 경사 21∼30°, 산사태위험등급 2등급 인 곳에 가장 많이 시공되었고, 임상환경인자인 임상, 경급, 영급, 밀도 중 소경급, Ⅲ영급 임분에서만 시공빈도가 유사하였다. 또한 사방댐의 크기 및 개소수를 결정하는 수문환경인자 중 유역면적의 경우 50ha 이하, 수계밀도 2.1∼4.0km/km2, 종장형 수계, 1시간당 최대강수량 61∼90mm, 1일 최대강수량 201∼300mm인 곳에서 가장 많이 시공되었다. 따라서 사방댐 시공지와 계류보전시설지 간의 입지 및 수문조건이 다소 유사한 것으로 추후 야계사방사업을 실시할 경우 산각붕괴 및 침식 발생위험이 높은 지역에 한해서는 사방댐과 계류보전시설의 병행이 가능한 것으로 판단된다.

Activated sludge sewage treatment processes are difficult to be controlled because of their complex and nonlinear behaviour, however, the control of the dissolved oxygen level in the reactors plays an important role in the operation of the facility. For this reason, this study is designed to present a system which accurately measures DO, MLSS, pH and ORP in the aeration tank to alleviate situations above and provide the automatization of a sewage treatment plant (STP) using new DO control system. The automatic control systems must be guaranteed the accuracy. Therefore, the proposed automatic DO control system in this study could be commercial applications in the aeration tanks by means of operating cost analysis and user-friendly for operation and maintenance. We could get accurate data from the lab tank which has water quality checker because there was no vortex and air bubble during the measurement process. Improvement of confidence in the lab tank enabled effective and automatic operation of sewage treatment plants so that operation costs and manpower could be saved. If this result is put in place in every sewage treatment plant nationwide for practical purposes, it is estimated to cost 18.5 million dollars in installing the lab tank and to save 9.8 million dollars in management cost a year, except for cost saved by automation.

It is analysised the causes and extent of damage of natural disasters through the investigating of natural disaster states occurred in Gyeongsangnam-do. The data for this study were based on disaster annual report between 1987 and 2003. Especially, the data between 1993 and 2003 were used for the analysis in Gyeongsangnam-do area. A typhoon and a heavy rain were the major causes of the natural disasters in Gyeongsangnam-do. For all that the extent of damage by a heavy rain was twice as much as that of a typhoon, Gyongsangnam-do suffered heavy damage from a typhoon. So, special attentions should be paid to establish prevention plans for that in this area. Also, half of the natural disasters were occurred between July and August, the intensive prevention plans for the summer season are needed.

Fuzzy algorithm of automatic control for dissolved oxygen(DO) concentration in the aeration tank of an activated sludge process is proposed. Among variables repirometry and air flowrate are selected as significant input factors and the relationship with DO is estimated using a multiple regression model. The DO concentration and the amount of repirometry are fuzzified and the fuzzy rule base are determined. Using the fuzzy algorithm, the change of amount of air flowrate are determined and the change of amount of DO is derived.